高强钢焊接后裂纹缺陷原因分析

Analysis on the causes of cracks and defects in high strength steel after welding

针对高强度钢Q690(厚度规格≥40 mm)经焊接后,靠近焊缝位置的母材出现细小裂纹,通过分析金相组织及钢板厚度截面偏析情况,同时对钢板夹杂物类型进行确认。结果表明:高强钢板厚度方向中心位置产生的微裂纹,是由C、P等元素严重偏析及偏析带内存在一定数量的MnS、TiN等高熔点夹杂物,焊接后在应力的作用下产生裂纹。

After welding of high-strength steel Q690(thickness specification≥40 mm),small cracks appeared in the base metal near the weld seam.By analyzing the metallographic structure and section segregation of the steel plate thickness,the type of inclusions in the steel plate was confirmed.The results indicate that the microcracks generated at the center of the thickness direction of the high-strength steel plate are caused by severe segregation of elements such as C and P,as well as a certain amount of high melting point inclusions such as MnS and TiN in the segregation zone.After welding,cracks are generated under stress.